I, at least, was very stupid in this case, for I had my head full of earthquakes, and convulsions of nature, and all sorts of prodigies which never happened to this glen; and so, while I was trying to find what was not there, I of course found nothing.

But when I put them all out of my head, and began to look for what was there, I found it at once; and lo and behold! I had seen it a thousand times before, and yet never learnt anything from it, like a stupid man as I was; though what I learnt you may learn as easily as I did.
And what did I find?
The pond at the bottom of the glen.
You know that pond, of course?
You don't need to go there?
Very well.
Then if you do, do not you know also that the pond is always filling up with sand and mud; and that though we clean it out every three or four years, it always fills again?
Now where does that sand and mud come from?
Down that stream, of course, which runs out of this bog.

You see it coming down every time there is a flood, and the stream fouls.
Very well.

Then, said Madam How to me, as soon as I recollected that, "Don't you see, you stupid man, that the stream has made the glen, and the earth which runs down the stream was all once part of the hill on which you stand." I confess I was very much ashamed of myself when she said that.

For that is the history of the whole mystery.